Retractable needle for blood gas sampling

ABSTRACT

A medical device having a frontal attachment and a connector housing having at least a body part of an associated medical apparatus, the frontal attachment slidably engaging the connector housing and having a forwardly projecting, rearwardly biased needle and a needle retraction assembly, and the connector housing having a needle retraction cavity laterally offset from the needle in a first position, the needle retraction cavity being selectively movable relative to the frontal attachment following use to reposition the needle retraction cavity into alignment with the needle to permit retraction. The subject device is desirably specially modified for use in blood gas sampling by the addition of a filter plug.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119(e) of U.S.Provisional Appl. No. 61/906,313 filed Nov. 19, 2013. This applicationalso claims priority as a continuation-in-part of U.S. patentapplication Ser. No. 14/020,440 filed Sep. 6, 2013, which claimed thebenefit of U.S. Provisional Appl. No. 61/836,723 filed Jun. 19, 2013.This application also claims priority as a continuation-in-part of U.S.patent application Ser. No. 14/091,113 filed Nov. 26, 2013, whichclaimed the benefit of Provisional Appl. No. 61/737,263, filed Dec. 14,2012.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is a medical device having a frontal attachmentcomprising a retractable needle. One aspect of the invention relates toa frontal attachment that desirably clips onto and in sliding engagementwith a connector housing comprising a unitarily molded or otherwiseformed needle retraction cavity and at least a body or barrel portion ofan associated medical device in laterally spaced-apart relation to eachother. The associated medical device can include, for example, asyringe, IV-catheter insertion device, infusion set, fluid collectiondevice, or other medical apparatus with which a retractable needle canbe used. One preferred embodiment of the invention relates to a medicaldevice comprising a retractable needle that is selectively attachable toa conventional needless syringe or other cooperatively attachablevascular fluid collection apparatus, the device being specially adaptedfor use in sampling blood gas, and more particularly, for samplingarterial blood gas.

Another aspect of the invention relates to a frontal attachment having arearwardly biased retractable needle and a needle retraction mechanism,wherein the needle is aligned longitudinally with a fluid flow paththrough the connector housing to the associated apparatus whenever fluidis flowing through the needle but is not aligned with a needleretraction chamber until needle retraction is initiated.

Another aspect of the invention relates to a connector housing desirablycomprising a needle retraction chamber open at one end and having aneedle retraction cavity with a longitudinal axis that is substantiallyparallel to but laterally offset from the longitudinal axis orcenterline of the needle during use and prior to needle retraction.

Another aspect of the invention relates to a connector housing that isdesirably engaged with and slidable in relation to a frontal attachmentin a direction substantially transverse to the longitudinal axis througha retractable needle seated in the frontal attachment. The slidablemovement is desirably initiated by applying opposed forces to at leastthe frontal attachment and the connector housing. One of the oppositelydirected forces can be a resistance force.

Another aspect of the invention relates to a medical device inside whicha retractable needle holder and needle seated in a frontal attachmentprior to use are biased into a safe position following use so that theneedle tip is not exposed and the frontal attachment device cannot bereused. When the needle and needle holder are in the “safe position,”the needle holder and a portion of the needle are desirably disposed ina retraction cavity inside a needle retraction chamber that is notcoaxially aligned with the needle when fluid is passing through theneedle during use of the medical device.

2. Description of Related Art

Conventional syringes comprising a generally cylindrical barrel, aneedle projecting forwardly from the barrel, and a plunger slidablydisposed inside the barrel through an opening in the rear of the barrelare well known. Some conventional syringes are made with a luer slip orluer lock connector on the front of the barrel to which a cooperativelyconfigured changeable needle or needle hub is attachable to allowneedles of different gauges or sizes to be used. The luer tips of suchsyringes are typically exposed to bacterial or viral contamination byincidental contact with a person or object during use. A notableexception is U.S. Pat. No. 8,343,094, which discloses a syringe that canbe used with a changeable needle and also has a protective guardstructure that extends forwardly past the luer tip to reduce thelikelihood of contamination by contact.

More recently, syringes and other medical devices having fixed orchangeable needles have been designed to embody various “safety”elements in an effort to control the spread of blood-borne pathogens andcontamination by contact with exposed needles, bodily fluids or othercontaminated objects or surfaces. Such devices sometimes includeretractable needles, as in U.S. Pat. No. 7,351,224, but the term“safety” is also frequently applied to products having moveable guards,shields or covers that must be manipulated manually to cover or blockaccess to the tip of a needle that is not retractable following use. Useof such moveable guards, shields or covers is not effective unless theneedle is first removed from the patient or another device in relationto which fluid has been injected or extracted. The use of productshaving moveable guards, shields or covers as “safety” elements has insome cases been reported to increase the number of accidentalneedle-sticks, and such devices should be distinguished from thosehaving retractable needles, and especially from those having needlesthat can be retracted while still inserted into a patient or otherdevice. Examples of devices incorporating a “safety” element that is nota retractable needle are disclosed in U.S. Pat. No. 5,370,628 and U.S.Pat. No. 8,500,690. U.S. Pat. No. 8,500,690 acknowledges that the safetyshield disclosed there cannot fully encompass the needle cannula untilit is fully removed from the patient and also acknowledges thatautomatic shielding may be triggered by the intentional or unintentionalrelease of the finger tabs by the user at any time following removal ofthe packaging cover.

In the previously known medical devices having retractable needles andneedle retraction mechanisms, a needle retraction cavity is typicallyprovided that is aligned with the longitudinal axis through the needleduring use. In such devices a barrel and/or a cylindrical interiorportion of a plunger handle often serve as the needle retraction cavity.An example of such a device is disclosed in U.S. Pat. No. 7,351,224.

In other medical devices, the needle retraction cavity is made as aunitary part of a body comprising both a barrel and a needle retractioncavity, each having a longitudinal axis that is substantially parallelto and spaced apart from the longitudinal axis of the other during use.In those devices, however, the needle and needle retraction cavityremain aligned during both use and needle retraction, and a cross-overfluid pathway is provided between the barrel and the rear end of theneedle. An example of such a device in which the needle is notrearwardly biased is disclosed in U.S. Pat. No. 4,941,883. An example ofsuch a device in which the needle is rearwardly biased is disclosed inU.S. Pat. No. 6,468,250.

Among the medical devices having retractable needles, some have anactuator to which a retraction force is manually applied to retract theneedle by sliding it rearwardly into a needle retraction cavityfollowing use. Other devices either automatically retract the needleinto a needle retraction cavity following use or require a separate andsubsequently applied manual force to initiate needle retraction. Themanual force needed to initiate needle retraction is sometimes appliedlongitudinally, such as through all or a portion of a plunger toreposition a plug or retainer member or to cut, fracture or pierce aninterfering element. Such devices are disclosed, for example, in U.S.Pat. No. 5,503,010 and in U.S. Pub. No. 2008/0287881. Sometimes theinitiating manual force is applied by pivoting a trigger element into anangular relationship with the longitudinal axis of the needle toreposition an element interfering with the retraction of a rearwardlybiased element as shown, for example, in U.S. Pub. No. 2010/0317999.Sometimes the initiating force is applied by lateral movement of anactuator disposed inside a housing that comprises a needle retractionmechanism as disclosed, for example, in U.S. Pub. No. 2009/0306601.Sometimes the initiating force is applied by depressing a lever bar in adirection transverse to the longitudinal axis through the needle to pulla trigger pin and thereby release a slidable piston assembly biasedrearwardly by a spring as disclosed, for example, in U.S. Pat. No.4,973,316. A few known medical devices, as disclosed for example in U.S.Pat. No. 7,351,224, have needle retraction mechanisms with rearwardlybiased needles that enable the needle to be retracted directly from thepatient, but many others do not.

Another known medical device, disclosed in European Application No. EP 0479 303 A1, is a frontal attachment for a luer tip syringe in which thefrontal attachment comprises a needle retraction cavity having alongitudinal axis that is parallel to and spaced apart from thelongitudinal axis of a connector portion to which a luer tip of thesyringe is connected. With that device, however, the needle is coaxiallyaligned with the retraction cavity at all times and a fluid pathway isprovided for fluid cross-over between the syringe and the needle. Also,even though the syringe with which the syringe can be used ischaracterized as “conventional” in the disclosure, the plunger portionof the syringe is specially adapted by the addition of a pushrodextending forwardly from the plunger seal that cooperates with thefrontal attachment. Needle retraction in the device is initiatedmanually with an assist provided by a tensioned rubber band connected tothe distal end of the retraction cavity.

Although the safety benefits of medical devices having retractableneedles have become more widely recognized and appreciated in recentyears, in the interest of safety for patients, their families and healthcare workers, a need remains for medical devices having an economicaland reliable frontal attachment for use with medical apparatus such as aconventional syringe or IV-catheter introducer having a luer lock orluer slip connector. The needed devices should be usable withoutrequiring special adaptation or modification of an associated medicalapparatus (such as a syringe), have few parts, be comparativelyinexpensive to manufacture, and embody a selectively attachable,retractable needle of a desired size and a needle retraction mechanismthat can be activated with one hand and will retract the needle directlyfrom a patient without applying a force during needle retraction.

SUMMARY OF THE INVENTION

The invention disclosed here is a medical device comprising a frontalattachment and a connector housing. The subject frontal attachment andthe connector housing are desirably selectively attachable and aremaintained in closely spaced, slidable relation to each other by one ormore structural elements connected to one or both of them. In oneembodiment of the invention, the frontal attachment desirably clips ontoand slidably engages the connector housing, and a stop member isprovided to prevent over-travel or disengagement. The connector housingalso desirably comprises as an integral portion of the device at leastpart of an associated medical apparatus with which a retractable needlecan be used. Such associated medical apparatus can include, for example,a syringe, IV-catheter insertion device, infusion set, or fluidcollection device. The connector housing desirably further comprises aneedle retraction chamber and a needle retraction cavity, both of whichhave a common longitudinal axis that is offset from and not aligned withthe longitudinal axis of the needle during use of the medical device andprior to needle retraction.

In one embodiment of the invention, the frontal attachment comprises abody, a needle retraction assembly seated inside the body, and aforwardly projecting needle. The needle retraction assembly desirablyincludes a needle holder and a biasing member that biases the needleholder rearwardly in relation to the body. The forwardly projectingneedle is desirably supported by the needle holder seated inside thebody of the subject frontal attachment, and the needle holder is biasedrearwardly. A satisfactory biasing member is a compressed coil springthat is held in compression when the body is attached to the connectorhousing, although other similarly effective biasing devices can also beused.

The connector housing desirably further comprises a needle retractionchamber having at least one unobstructed, forwardly facing, open endcommunicating with a rearwardly extending needle retraction cavity. Ifdesired, a small vent can also be provided at or near the rear end ofthe needle retraction cavity. The connector housing is desirablyunitarily molded together with at least a part of the associated medicalapparatus, although other substantially rigid attachment means such asadhesives, plastic welding or the like can also be used to join a partof an associated medical device, such as a syringe barrel, in asubstantially fixed positional relationship to the needle retractionchamber of the connector housing. Whether the connector housing isunitarily molded together with or is otherwise attached to and made anintegral part of at least a portion of the associated medical apparatus,the connector housing desirably establishes a substantially linear fluidflow path between the associated apparatus and the needle holder(without the need for cross-over channels or the like), thereby reducingthe pressure required to move fluids from one to the other as comparedto a non-linear flow path as might be experienced in a device having across-over channel between a fluid chamber and the retractable needle.

A fluid seal is desirably disposed between the frontal attachment andthe connector portion of the connector housing, and is seated in arecess disposed in coaxial alignment with the connector portion of theconnector housing in coaxial alignment with the needle prior toretraction. In one embodiment of the invention, the fluid seal isannular and is movable so that it remains aligned with the connectorportion of the connector housing and is repositioned into facing contactwith the rear of the body of the frontal attachment as needle retractionis initiated. The annular fluid seal desirably surrounds the fluid flowpath between the connector housing the body of the frontal attachmentprior to needle retraction and restricts fluid leakage between facingsurfaces of the body and connector housing prior to, during and afterneedle retraction. The needle retraction cavity inside the needleretraction chamber of the connector housing is initially offset from thelongitudinal axis through the needle but is desirably moved laterallyinto substantial alignment with the needle axis during needleretraction. A locking needle cap is desirably provided to preventpremature activation of the needle retraction mechanism duringpackaging, shipping and handling, and to protect the needle tip frombeing blunted, bent or otherwise damaged prior to use.

The medical device of the invention can also comprise a filter plug tofacilitate use of the device for collecting and transferring blood gassamples for further processing. Following collection of a blood samplealso containing arterial blood gas, the needle of the subject device canbe retracted by shifting the needle or the needle retraction cavitylaterally relative to the other so that the needle is aligned with theneedle retraction cavity, which also shifts the filter plug intoalignment with the fluid flow path into the syringe. If desired afterneedle retraction, the syringe can be rotated to a more verticalposition, thereby allowing the excess air to flow upwardly, after whichthe plunger is advanced until blood touches the filter, at which timethe syringe is ready for further processing.

Needle retraction is desirably initiated by steadying or stabilizing thesubject medical device relative to the patient and then applyingpressure, desirably with one hand, to move the needle retraction cavityand the connector housing relative to the frontal attachment until theretraction cavity is substantially coaxially aligned with thelongitudinal axis of the needle. As shown in one embodiment, an optionaltextured contact surface is disposed on at least one of the frontalattachment and the connector housing, respectively, to facilitateapplication of opposed or oppositely directed forces. Manual pressure isdesirably applied in facing directions along an axis that issubstantially parallel to a sliding interface between the frontalattachment and the connector housing, and substantially transverse tothe laterally spaced longitudinal axes through the needle and the needleretraction chamber. As used herein, the term “sliding interface” refersto an interface that permits relative sliding movement between facingsurfaces of the frontal attachment and the connector housing. It shouldbe appreciated, however, that one of the oppositely directed forcesapplied to initiate needle retraction in the subject medical device canbe a resistance force. Although not shown in the accompanying drawings,it will also be appreciated upon reading this disclosure that similarlyeffective but more complex apparatus can be substituted for the manualpressure used to initiate needle retraction. For example, one canincorporate into the subject medical device another biasing means suchas a spring-activated or other similarly effective mechanism toreposition the needle retraction cavity into substantial coaxialalignment with the needle to facilitate needle retraction following useof the device. As will be apparent to those of ordinary skill in the artupon reading this disclosure, the use of such a biasing means will alsorequire a release or triggering element to release the bias and therebyinitiate relative sliding movement between the frontal attachment andthe connector housing.

When the opening into the retraction cavity is sufficiently aligned withthe head of the needle holder to receive the needle holder into theneedle retraction cavity, a biasing member such as a compressed coilspring disposed in the body propels the needle holder and needlerearwardly, simultaneously withdrawing the beveled front tip of theneedle so that it no longer projects forwardly from the body of thefrontal attachment. As the needle retraction chamber slides laterallyrelative to the needle, the annular fluid seal reduces the likelihood ofany fluid leakage from the subject medical device due to fluid flow outof the associated medical apparatus following use.

The subject medical device provides numerous benefits and advantageswhen compared to prior art devices. Once such benefit is that needleretraction can be activated independent of aspiration so that, forexample, fluid can be withdrawn from a knee and the needle can still beretracted without fully depressing the plunger handle. Another benefitis that the subject medical device is configured to retract the needledirectly from a patient without first having to manually withdraw theneedle and risk possible contamination by exposure to bodily fluidscontaining infectious pathogens. Needle retraction can also be initiatedfollowing injection of a partial dose. Greater control can be exercisedby the clinician using the invention because retraction is initiated byapplying pressure closer to the base of the device, thereby reducing thelikelihood of needle “wobble” in the patient.

In one embodiment of the invention, the subject medical device is alsoprovided with a needle cap or needle cover that releasably engages thebody and locks the connector housing into a position where it cannot bemoved sufficiently to permit premature activation of the needleretraction mechanism without first removing the needle cap. If desired,the subject medical device can itself be used as a cover, closure or capfor a prefilled syringe. When made in combination with a syringe barrel,for example, the subject frontal attachment can be used to draw up adose of expensive or caustic drugs or medicines and then capped forlater use to avoid waste or injury. While the needle cap or cover is inplace, the medical device of the invention can also be convenientlycarried in a pocket or clipped inside of or onto it, particularly whenconfigured as described below.

If desired, the subject medical device can be rigidly mounted to,integrally molded with, or otherwise manufactured or assembled as atleast part of an associated medical apparatus. As one example, theconnector housing and syringe barrel are unitarily or integrally moldedfrom a moldable, medical grade polymeric resin. As another example, asyringe barrel is otherwise attached or connected in substantially fixedrelation to the connector portion of the connector housing and isdisposed in substantially coaxial alignment with the needle retractionassembly and the needle prior to movement of the connector housingrelative to the frontal attachment following use but prior to needleretraction. In this embodiment, the substantially parallel, centrallydisposed longitudinal axes through the needle retraction chamber andneedle retraction cavity are still desirably spaced laterally apart fromeach other even if the needle retraction chamber and syringe barrel areunitarily or integrally molded in such manner that they are side by sidewith no open space between them so that part of the needle retractionchamber and part of the syringe barrel share a common wall. Severalbenefits can be achieved through use of this embodiment, and it can bepackaged and sold in combination with a plunger and plunger seal thatcooperate to create a variable volume fluid chamber inside the devicethat is aligned with the needle and enables the device to be used eitherto inject or withdraw fluids through the needle under either positive ornegative pressure.

The frontal attachment of the invention can also be used with needlesand syringes of different and varying gauges and sizes without specialmodification. If desired, either the associated medical apparatus withwhich the subject medical device is used, or the medical device itself,can be provided with a plug containing an anticoagulant such as heparinto use in blood gas applications. The structure and operation of theinvention are simplified by the provision of a substantially linearfluid flow path and a needle retraction chamber and associatedretraction cavity that are offset laterally from the fluid flow pathduring fluid injection or extraction. The subject medical device has fewparts, and those are easily and inexpensively molded.

The medical device of the invention also embodies safety features thatare not typically available in many prior art devices. For example, thesubject device is effectively “locked shut” against reactivation andreuse by the spring and needle that bridge the needle retraction cavityand body together following retraction. The sliding lateral movement andassociated repositioning of the needle retraction cavity relative to thefluid flow path through the connector housing and the presence of afluid seal between the body and connector housing cooperate to interruptthe fluid flow path and prevent fluid backflow from an associatedmedical apparatus following use. After the needle is retracted, thesubject medical device can be removed from the associated medicalapparatus and disposed of as with other needle covers. In circumstanceswhere the associated medical apparatus is reusable, it can beautoclaved, sterilized or otherwise processed for possible reuseindependently of the needle-containing component.

Other benefits and advantages of the subject medical devices willlikewise become more apparent to those of ordinary skill in the art uponreading this disclosure in relation to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The apparatus of the invention is further described and explained inrelation to the following drawings wherein:

FIG. 1 is a right front perspective view of an embodiment of the medicaldevice of the invention with the needle cover installed;

FIG. 2 is a left front perspective view of the medical device of FIG. 1;

FIG. 3 is the medical device as in FIG. 1 with the needle cover removed;

FIG. 4 is the medical device as in FIG. 2 with the needle cover removedand prior to needle retraction;

FIG. 5 is an exploded front perspective view of the medical device as inFIG. 1 (exploded along the longitudinal axis through the retractableneedle assembly of the frontal attachment and the connector portion ofthe connector housing);

FIG. 6 is a front elevation view of the medical device of FIGS. 1 and 2;

FIG. 7 is a front elevation view of the medical device of FIGS. 2 and 3,with the needle cover removed;

FIG. 8 is a rear elevation view of the medical device as in FIG. 7;

FIG. 9 is a top plan view of the medic al device of FIG. 1;

FIG. 10 is a right side elevation view of the medical device of FIG. 1;

FIG. 11 is a cross-sectional plan view of the medical device in apre-use position, taken along line 11-11 of FIG. 10, and also showing inphantom outline a conventional luer lock syringe attached to theconnector housing of the subject medical device;

FIG. 12 is a top plan view of the medical device and syringe of FIG. 11,with the syringe again shown in phantom outline;

FIG. 13 is a cross-sectional plan view of the medical device as in FIG.11, but with the needle cover removed and the syringe plunger withdrawnto an aspirated position;

FIG. 14 is a top plan view as in FIG. 12, but with the needle coverremoved and the syringe plunger withdrawn to an aspirated position;

FIG. 15 is a top plan view as in FIG. 13, but with the syringe plungerfully depressed to a post-injection position and with the needle fullyretracted;

FIG. 16 is a right front perspective view of the subject medical devicefollowing detachment from a syringe and with the needle in the fullyretracted position;

FIG. 17 is a right side elevation view of the medical device of FIG. 16;

FIG. 18 is a top plan view of the medical device taken along line 18-18of FIG. 17;

FIG. 19 is a rear elevation view of the medical device of FIG. 16;

FIG. 20 is a left rear perspective view of the body portion of thefrontal attachment;

FIG. 21 is a right rear perspective view of the body portion of thefrontal attachment;

FIG. 22 is a cross-sectional side elevation view taken along line 22-22of FIG. 6;

FIG. 23 is a left front perspective view of the medical device as inFIG. 4 but having the needle cover removed and following needleretraction;

FIG. 24 is a right front perspective view of another embodiment of themedical device of the invention wherein the associated medical apparatusis a syringe having a body portion that is integrally molded as part ofthe connector housing and wherein the removable needle cover as depictedin relation to the embodiment disclosed above is not shown;

FIG. 25. is a right front perspective view as in FIG. 24 wherein aplunger handle of the associated medical apparatus is fully depressedand the needle is retracted;

FIG. 26 is a right side elevation view of the medical device as in FIG.24 but with the needle cover shown;

FIG. 27 is a cross-sectional top plan view of the medical device as inFIG. 26;

FIG. 28 is an exploded front perspective view of the medical device asin FIG. 26;

FIG. 29 is a cross-sectional top plan view taken along line 29-29 ofFIG. 31 showing the needle in the post-retraction position;

FIG. 30 is a front elevation view of the medical device of FIG. 26;

FIG. 31 is a front elevation view of the medical device of FIG. 26following removal of the needle cover and also following needleretraction;

FIG. 32 is a rear elevation view of the medical device of FIG. 30;

FIG. 33 is a rear elevation view of the medical device of FIG. 31following removal of the needle cover and also following needleretraction;

FIG. 34 is a right front perspective view of another embodiment of thesubject medical device in which a syringe barrel is molded together withthe connector housing of the invention and showing a removable needlecover in place over the retractable needle and a plunger inserted intoan opening at the rear of the syringe barrel;

FIG. 35 is the medical device of FIG. 34 with the needle cover removedand the retractable needle projecting forwardly from the frontalattachment in the use position;

FIG. 36 is the medical device of FIG. 35 with the plunger handle morefully depressed inside the syringe barrel and with the needle retractionchamber and needle retraction cavity moved laterally with respect to thefrontal attachment and needle retracted;

FIG. 37 is an exploded right perspective view of the medical device ofFIG. 34;

FIG. 38 is a right side elevation view of the medical device of FIG. 34;

FIG. 39 is a cross-sectional top plan view of the medical device of FIG.38;

FIG. 40 is a top plan view of the medical device of FIG. 39 with theneedle cover removed;

FIG. 41 is a top plan view of the medical device of FIG. 40 with theplunger more fully depressed into the syringe barrel, with the connectorhousing repositioned laterally relative to the frontal attachment toalign the needle retraction chamber and needle retraction cavity withthe needle retraction assembly and with the needle retracted;

FIG. 42 is a cross-sectional top plan view of the medical device of FIG.41;

FIG. 43 is a rear elevation view of the frontal attachment of themedical device of FIG. 37;

FIG. 44 is a cross-sectional view taken along line 44-44 of FIG. 43,with portions broken away to simplify the view and better illustrate theresilient polymeric clips used to slidably engage the frontal attachmentto the base of the connector housing;

FIG. 45 is an exploded perspective view of a retractable needle assemblycomprising a filter plug suitable for use in sampling blood gas;

FIG. 46 is a right side elevation view of the assembled apparatus ofFIG. 45 without the needle cap and prior to needle retraction;

FIG. 47 is a cross-sectional view taken along line 47-47 of FIG. 46;

FIG. 48 is a front elevation view of the apparatus of FIG. 46;

FIG. 49 is a rear elevation view of the apparatus of FIG. 46;

FIG. 50 is a right side elevation view of the apparatus of FIG. 46following needle retraction;

FIG. 51 is a cross-sectional view taken along line 51-51 of FIG. 50;

FIG. 52 is a front elevation view of the apparatus of FIG. 50;

FIG. 53 is a rear elevation view of the apparatus of FIG. 50;

FIG. 54 is a right side elevation view of the apparatus of FIG. 46having a syringe attached and prior to needle retraction;

FIG. 55 is a cross-sectional view taken along line 55-55 of FIG. 54;

FIG. 56 is a front elevation view of the apparatus of FIG. 54;

FIG. 57 is a right side elevation view of the apparatus of FIG. 54following needle retraction;

FIG. 58 is a cross-sectional view taken along line 58-58 of FIG. 57; and

FIG. 59 is a front elevation view of the apparatus of FIG. 57.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIGS. 1, 2 and 10, medical device 30 comprises connectorhousing 32, frontal attachment 34 and locking needle cover 36. Referringto FIGS. 3, 4 and 9, locking needle cover 36 is removed to reveal needle38 with upwardly facing beveled tip 40. Referring to FIGS. 5 and 9,connector housing 32 of medical device 30 desirably further comprisesneedle retraction chamber 42 having rearwardly facing closed end 44 andforwardly facing opening 46 bounding retraction cavity 58. Opening 46 isdesirably elongated or oval shaped, with a transverse dimension greaterthan the inside diameter of the elongate cylindrical portion of needleretraction chamber 42. As seen in FIGS. 5-8, opening 46 desirablytransitions along tapered inside wall 102 (back 103 visible in FIG. 8)to the inside diameter of needle retraction chamber 42. Tapered insidewall 102 facilitates insertion and removal of locking arm 98 of lockingneedle cover 36, and also facilitates the entry of needle holder 72 andretraction spring 80 into retraction cavity 58 during needle retraction,as is discussed in greater detail below. If desired, closed end 44 canalso comprise a small opening (such as for venting purposes) providedthat it is not large enough to permit the needle retraction spring 80,needle holder 72 or needle 38 from exiting through the rear of needleretraction chamber 42.

As depicted in FIG. 5, connector housing 32 desirably further comprisesconnector 48 for use in attaching medical device 30 to an associatedmedical apparatus such as, for example, syringe 104, which is shown anddescribed in relation to medical device 30 in FIGS. 11-15. Connector 48comprises a substantially cylindrical sidewall having an internal fluidflow path 54 with forwardly facing opening 52 and rearwardly facing openend 50. Two diametrically disposed, radially projecting luer lockingtabs 56 are provided near rear end 50 for use in attaching connector 48to an associated medical apparatus. Forwardly facing opening 52desirably further comprises a recessed annular seating surface forreceiving fluid seal 68. Fluid seal 68 also desirably comprises acentrally disposed fluid flow path 70 that is coaxial with fluid flowpath 54 through connector 48. Referring to FIGS. 4 and 6-10, a textureddigital contact surface 100 is desirably but optionally provided on theoutwardly facing surface of needle retraction cavity 42 to facilitatethe application of manual force (indicated by arrow 35 in FIG. 4) toconnector housing 32 for use when initiating needle retraction, asdiscussed below.

Still referring to FIG. 5, frontal attachment 34 of medical device 30further comprises a base 82 and forwardly projecting needle support 84.Needle support 84 preferably has a plurality of spaced-apart, taperedribs 88 to provide releasable frictional engagement with the inside ofcollar 97 of locking needle cover 36, although it will be appreciated bythose of ordinary skill in the art upon reading this disclosure thatother similarly effective means can be provided for releasably securinglocking needle cover 36 to needle support 84. Referring to FIGS. 5 and20-22, base 82 and needle support 84 desirably comprises a steppedinternal bore 86. Referring more particularly to FIGS. 20-21, base 82further comprises rearwardly facing surface 87 with an opening intostepped internal bore 86 that desirably comprises an annular recessconfigured to receive and seat the larger diameter head portion 76 ofneedle holder 72 (visible in FIG. 5) when needle retraction mechanism(FIG. 5) comprising compressed spring 80 and needle holder 72 isinserted into frontal attachment 34 prior to the attachment of frontalattachment 34 to connector housing 32. An outwardly facing, texturedcontact surface 90 is desirably but optionally provided at the end ofbase 82 for use in applying a force as indicated by arrow 45 in FIG. 4during needle retraction, as discussed in greater detail below. Theforce applied to frontal attachment 34 can be a resistance force, andpreferably comprises a major component that is opposed or oppositelydirected relative to the force applied as indicated by arrow 35 inrelation to connector housing 34.

Referring generally to FIGS. 1-23 and more specifically to FIGS. 5-8 and19-23, during assembly of medical device 30, the forward end of coilspring 80 is desirably inserted into and seated inside bore 86, andelongate tubular shaft portion 74 of needle holder 72 is desirablyinserted into coil spring 80 and forced downwardly to compress thespring and allow the larger diameter head 76 of needle holder 72 to beseated inside bore 86. This causes compressed spring 80 to exert arearwardly directed biasing force against the underside of head 76.Needle holder 72 desirably comprises a longitudinally extending bore 78that is placed in fluid communication with needle 38 when needle 38 isinstalled inside the forwardly extending portion of bore 78. Accordingto one embodiment of the invention, a shallow recess is provided in therearwardly facing end of head 76 of needle holder 72 (not visible inFIG. 5) to releasably engage the forwardly facing end of fluid seal 68when medical device 30 is assembled. As shown in FIGS. 3 and 4, theforwardly extending end of needle holder 72 desirably projects slightlybeyond the forwardly extending tip of needle support 84 to facilitatethe attachment of needle 38 to needle holder 72 following installationof the needle retraction mechanism and attachment of frontal attachment34 to connector housing 32 by any suitable, conventional method known tothose of skill in the art. Although needle 38 can be attached to needleholder 72 either before or after installation of needle holder 72 insidefrontal attachment 34, attachment after installation of the needleretraction mechanism is preferred.

Following the insertion of fluid seal 68 into an annular recess insideforwardly facing opening 52 of connector housing 32 (as seen, forexample, in FIGS. 5 and 22), and while holding needle holder 72 insidefrontal attachment 34 against the rearwardly biasing force exerted bycompressed spring 80, rearwardly facing surface 87 of base 82 of frontalattachment 34 is positioned opposite the forwardly facing surface 60(seen in FIG. 5) of connector housing 32. Forwardly facing surface 60 ofconnector housing 32 is desirably configured to face and slidably engagethe rear 87 of base 82, as opposed rails 64, 66 (FIGS. 5, 8 and 19-23)of connector housing cooperatively engage opposed rails 91, 93,respectively, of base 82. Rails 64, 66 and 91, 93 are desirably made sothat they can snap into sliding engagement when connector housing 32 andfrontal attachment 34 are held in facing parallel alignment so that bore86 is disposed opposite opening 52 and squeezed together by applyingforce to the front of frontal attachment 34 and the back of connectorhousing 32 simultaneously. As frontal attachment 34 is attached toconnector housing 32, fluid seal 68 is squeezed into abutting contactwith the rearwardly facing end of head 76 of needle holder 72. Annularfluid seal 68 desirably prevents fluid leakage between connector housing32 and frontal attachment 34 during use of medical device 30 and anassociated medical device prior to repositioning connector housing 32relative to frontal attachment 34 prior to needle retraction.

Referring to FIGS. 5, 17 and 20, stop members 62, 63 are desirablyprovided to engage in abutting contact with opposed upper and lowershoulders (lower shoulder 65 visible in FIG. 20) of rear surface 87adjacent to base 82 of frontal attachment 34 to limit or restrict therange of lateral sliding motion of connector housing 32 relative tofrontal attachment 34 to prevent accidental separation. When medicaldevice 30 is assembled as described, head 76 of needle holder 72 (FIG.5) is seated inside recess 86 (FIGS. 19-20) in frontal attachment 34,and a substantially linear fluid pathway is desirably defined throughbore 54 of connector 48, bore 70 of fluid seal 68, bore 78 of needleholder 72, and needle 38.

Referring to FIGS. 1-3, 5-6 and 11, locking needle cover 36 desirablycomprises a substantially cylindrical sidewall 92 having closed end 94,open end 96, and a plurality of longitudinally extending, externalreinforcing ribs to provide rigidity needled to protect needle 38 fromdamage prior to use. Locking arm 98 desirably projects rearwardly fromcollar 97 of locking needle cover 36 and is configured to be insert ableinto opening 46 of connector housing 32 to restrict relative slidingmovement between connector housing 32 and frontal attachment 34 prior toremoval of locking needle cover 36 from needle support 84. Othersimilarly effective locking structures can likewise be provided withinthe scope of the invention, and it will be appreciated that such lockingstructures are not required to be part of the needle cover. FIGS. 6 and7, respectively, show medical device 30 as viewed from the front withand without locking needle cover 36 in place.

Referring to FIGS. 11-15, an associated medical apparatus is shown inphantom outline in combination with medical device 30 of the invention.The associated medical apparatus is a conventional syringe 104 having agenerally cylindrical barrel 106 with a forwardly facing luer lockconnector and a plunger 108 having a plunger seal slidably engaging theinside wall of barrel. Plunger 108 cooperates with barrel 106 to definea variable-volume fluid chamber 110 inside the syringe that can supply afluid to needle 38 through the fluid pathway through medical device 30as described above. As shown in FIGS. 11 and 12, medical device 30 andsyringe 104 are depicted in fully assembled form with needle cover 36 inplace over needle 38. Plunger 108 is shown in a position relative tobarrel 106 that can be termed a “pre-injection” position such as that inwhich a conventional syringe without a needle might be packaged andshipped prior to use.

Referring to FIGS. 13 and 14, the fully assembled medical apparatus ofFIGS. 11 and 12 is shown again with the needle cover removed and withplunger 108 withdrawn to a position such as that in which fluid has beenaspirated into fluid chamber 110. Such aspiration could occur, forexample, by drawing fluid into the syringe from a vial or other fluidsource, or by extracting a fluid sample from a patient (followingexpelling air from fluid chamber 110). For prefill use, syringe 104 canbe filled to the desired level and packaged for shipment either with orwithout medical device 30 already in place.

Referring to FIGS. 13 and 15, following use of the fully assembledmedical apparatus, needle retraction is desirably achieved in medicaldevice 30 by repositioning connector housing 32 relative to frontalattachment 34 so that needle retraction chamber 42 is moved into coaxialalignment with needle 38. This can be done, for example, by manuallyapplying pressure (as indicated by arrow 35 in FIG. 4) to optionallyprovided contact surface 100 of connector housing 32 while stabilizingbarrel 106 and frontal attachment 34, and/or by applying resistancepressure (as indicated by arrow 45 in FIG. 4) to optionally providedcontact surface 90 of frontal attachment 34. If needle 38 is notinserted in a patient at the time of needle retraction, frontalattachment 34 and connector housing 32 can be repositioned relative toeach other by applying opposing manual pressure to contact surfaces 90and 100 or to other portions of frontal attachment 34 and connectorhousing 32. The application of pressure as disclosed above will causefluid seal 68 and connector housing 32 to move from a first position(FIG. 13 in which syringe 108 is aligned with needle 38 to a secondposition (FIG. 15) in which the needle retraction cavity of connectorhousing 32 is aligned with needle 38. As this repositioning occurs, therearwardly directed biasing force of spring 80 will cause needle holder72 and needle 38 to enter opening 46 when they are sufficiently alignedto permit full retraction. Similarly, if desired, medical device 30 canalso be constructed by biasing connector housing 32 relative to frontalattachment 34 so that the biased repositioning to permit needleretraction occurs upon application of a triggering force to acooperatively configured release element.

In FIG. 15, the fully assembled medical device of FIGS. 13 and 14 isshown again with plunger 108 fully depressed inside barrel 106 as itcould be following an injection, with connector housing 32 repositionedrelative to frontal attachment 34 from the position shown in FIG. 14 andwith needle holder 72, spring 80 and needle 38 all retracted intomedical device 30 in a safe position, with no part of needle 38 stillprojecting forwardly from frontal attachment 34. Following retraction,the expanded spring and the retracted needle can provide a “bridging”connection between frontal attachment 34 and connector housing 32 thatwill deter the removal of frontal attachment 34 from connector housing32 to reconfigure medical device 30 to its pre-retraction state, andwill also deter reverse movement of connector housing 32 relative tofrontal attachment 34 that could otherwise realign a fluid pathwaythrough medical device 30.

In FIGS. 16-18, syringe 104 has been detached from medical device 30 byunscrewing the luer lock connector, and medical device 30 is ready forsafe disposal. In FIG. 18, it is seen that fluid seal 68 remains inabutting contact with the back side of base 82 of frontal attachment 34around bore 70 following needle retraction.

Connector housing 32, frontal attachment 34 and needle cover 36 ofmedical device 30 are all desirably made from any moldable polymericmaterial approved for such medical applications and for sterilization.Fluid seal 68 is desirably made of an elastomeric polymeric materialhaving a composition and durometer that are satisfactory for containingfluids within the fluid pathway between connector housing 32 and frontalattachment 34 without degradation prior to and during use, and that willpermit disengagement from needle holder 72 and relative sliding movementbetween connector housing 32 and frontal attachment 34 as seal 68 andneedle retraction chamber 42 are repositioned laterally prior to needleretraction. Needle 38 is preferably made of stainless steel, anothermetal or alloy, or a ceramic or other material that is approved for suchuse. Compression springs are made of metal, are generally known in theindustry, and are readily available from commercial vendors.

Another embodiment of the subject invention is disclosed in relation toFIGS. 24-33 of the accompanying drawings. Referring to FIGS. 24 and 25,a medical device 200 is disclosed in which an associated medicalapparatus, in this case syringe barrel 222, is provided as a unitarypart of the connector housing. Medical device 200 desirably comprisesfrontal attachment 204 and connector housing 202, which are selectivelyattached to each other and are maintained by one or more attachmentmembers in closely spaced sliding relation to each other along at leastone sliding interface allowing limited sliding lateral movement betweenfrontal attachment 204 and connector housing 202 as previously discussedin relation to the embodiment of FIGS. 1-23. In FIG. 24, the needlecover (shown and described in relation to FIGS. 26-28 below) is removedto reveal needle 210. in FIG.

Frontal attachment 204 desirably further comprises body 206, forwardlyextending nose 208, retractable needle 210, and textured contact surface214. Connector housing 202 further comprises base 216, needle retractionchamber 218, and syringe barrel 222. In FIG. 24, the needle cover (shownand described in relation to FIGS. 26-28 below) is removed to show afirst position in which barrel 222 is coaxially aligned with needlesupport 208, laterally offset needle retraction chamber 218, and needleretraction cavity 220 having a forwardly facing opening that isunobstructed. In FIG. 25, connector housing 202 has been moved laterallyrelative to frontal attachment 204 to a second position in which needleretraction chamber 218 is substantially aligned with needle support 208,and needle 210 (no longer visible) has been retracted into needlesupport 208 and needle retraction cavity 220 (FIG. 24) inside needleretraction chamber 218.

In this embodiment of the invention, an associated medical apparatussuch as syringe barrel 222 (or other associated medical apparatuspreviously mentioned in this disclosure) is rigidly connected to andpart of the connector housing. In parts made with a moldable medicalgrade material, this substantially rigid connection can be achieved byany suitable method such as, for example, by unitarily or integrallymolding connector housing 202 comprising base 216, needle retractionchamber 218 and syringe barrel 222 as a single unit, or by using othersimilarly effect known technologies including, without limitation, theuse of laser welding or adhesives. When medical device 200 is configuredin this manner, needle retraction cavity 220 is considered to belaterally spaced apart from barrel 222 even though needle retractionchamber 218 and barrel 222 share a common wall (seen better in FIG. 27).It will also be appreciated that medical devices of the invention havingan attached associated medical apparatus can be made in which the needleretraction chamber and the associated medical apparatus do not share acommon wall. Referring again to FIGS. 24 and 25, laterally projectingbarrel flanges 224, 226 can also be integrally molded together as partof barrel 222 or can be separately fabricated and attached to the barrelby conventional methods. Plunger 228 is slidably disposed inside barrel222 and is shown in FIG. 24 in a typical position relative to barrel 222as it might be shipped and stored prior to use. As shown, plunger 228comprises handle 230, end cap 232 and plunger seal 238 (visible in FIGS.27-29). In FIG. 25, plunger handle 230 is more fully depressed relativeto barrel 222 as it would be in an injection application. For otherapplications, such as withdrawal of a bodily fluid from a patient, theplunger handle can also be withdrawn a greater distance relative tobarrel 222 than is shown in FIG. 24 when needle 210 is retracted.

Referring to FIG. 27, removable needle cover 234 is shown installed onmedical device 220, with locking arm 236 projecting into needleretraction cavity 220 to limit relative sliding movement between body206 of frontal attachment 204 (FIG. 26) and base 216 of connectorhousing 202 (FIG. 26) during shipment and handling prior to use. Withoutlocking arm 236 or another similarly effective structure holding needle210 in substantial coaxial alignment with fluid path 244 and fluidchamber 240 of barrel 222 prior to use, premature lateral shifting offrontal attachment 204 and/or connector housing 202 relative to theother could realign the retractable needle assembly comprising needleholder 246 and compressed needle retraction spring 250 with needleretraction cavity 220 sufficiently to allow spring 250 to expand anddrive needle holder 246 and needle 210 rearwardly into needle retractioncavity 220.

Referring to FIGS. 27-28, medical device 200 desirably further comprisesannular plunger seal 238 disposed on the forwardly facing end of plungerhandle 230 to provide sliding and sealing engagement with the insidewall of barrel 222 (FIG. 28). Referring to FIG. 28, connector housing202 desirably further comprises laterally spaced-apart, forwardly facingopenings 221 and 248. Opening 221 is provided to receive needle holder246 and expanded needle retraction spring 250 during needle retractionfollowing repositioning and realignment of connector housing 202relative to frontal attachment 204. Upper and lower stop members 245 andupper and lower rails 223 (lower rail not visible) are desirablyprovided to facilitate assembly of frontal attachment 204 to connectorhousing 202, provide at least one lateral sliding interface between themthat is substantially transverse to the longitudinal axis through needle210 and barrel 222, and provide stop members and cooperatively alignedblocking structures that preclude accidental disassembly as described ingreater detail above in relation to the first disclosed embodiment. Inone embodiment, stop members 245 and the upper and lower rails 223 arecooperatively configured so that frontal attachment 204 can be snappedinto sliding engagement with connector housing 202 and remain in slidingengagement with each other within a predetermined range of travel. Thepredetermined range of travel is desirably sufficient to permit movementbetween a first or initial position where needle 210 is aligned withbarrel 222 and a second or subsequent position where needle 210 isaligned with needle retraction cavity 218.

Referring to FIGS. 27-29 and 32, a fluid seal such as annular fluid seal242 is desirably provided to prevent fluid leakage around the fluidpathway 244 (FIG. 27) between opening 248 of connector housing 202 andthe rearwardly facing, annular end surface of needle holder 246. In thisembodiment, fluid seal 242 is desirably made of a medical gradeelastomeric material and is seated inside opening 248 of base 216 ofconnector housing 202. The length, radius, durometer of fluid seal 242and the inside diameter of fluid pathway 244 through fluid seal 242 aredesirably such that the forwardly facing end of fluid seal 242 can becompressed against the head of needle holder 246 without blocking oroverly restricting fluid flow through fluid pathway 244 during use.Referring to FIG. 29, following use of medical device 200, fluid seal242 is desirably carried by connector housing 202 as connector housing202 is repositioned relative to frontal attachment 204 to initiateretraction. During this repositioning, the forwardly facing end of fluidseal 242 is desirably moved away from needle holder 246 and intofluid-tight engagement with the opposed, rearwardly facing surface ofbody 206 (FIG. 32) of frontal attachment 204 to prevent any fluidleakage or flow-back from syringe 222. Although the use of an annularfluid seal 242 as described here is preferred, other similarly effectivefluid seals can also be employed within the scope of the invention.

Referring to FIGS. 29-33, following repositioning of connector housing202 from the first position to the second position as discussed above,needle retraction spring 250 expands rearwardly from needle support 208and drives needle holder 246 rearwardly into needle retraction cavity220 inside chamber 218, thereby retracting the front end of needle 210into needle support 208 or needle retraction cavity 220. The relativelengths of needle support 208, needle retraction cavity 220 and needleretraction spring 250 are desirably cooperatively sized according to therange of needle lengths with which medical device 200 is anticipated tobe used.

Although the medical device disclosed herein in relation to theembodiment of FIGS. 24-33 is in many respects similar to that disclosedin relation to the embodiment of FIGS. 1-23, medical device 200 offersseveral distinct advantages that are only available in an embodimentwhere an associated medical device such as a syringe is made as anintegral portion of the medical device. More particularly, the presenceof a syringe barrel in combination with a plunger such as a plunger 228having a slidable fluid seal such as plunger seal 238 allows thecreation of a variable volume fluid chamber such as fluid chamber 240within one device. Further, the user is afforded the ability to createeither a positive or negative pressure inside a fluid delivery orextraction device having a retractable needle and a needle retractioncavity that is not at any time disposed within the fluid pathway. Thisconfiguration enables a user to infuse or extract variable volumes ofvarious fluids having various viscosities at variable pressures suitablefor the intended application without risk of blowout or premature needleretraction. Further, the subject device provides all the safety benefitsassociated with one-handed use and retraction with a needle that can beretracted directly from a patient following use and into a safe positionwhere the needle cannot be reused. Further, the simple and compactdesign, with few moving parts and lower manufacturing and assemblycosts, will desirably enhance its potential for widespread use.

Another embodiment of the subject invention is disclosed in relation toFIGS. 34-44 of the accompanying drawings. This embodiment is similar tothe embodiment of FIGS. 24-33 in that it comprises a part of anassociated medical device that is an integral part of the connectorhousing. In the embodiment shown in FIGS. 34-44, the associated medicaldevice is a syringe. Referring generally to those drawing figures,medical device 300 desirably comprises a connector housing 302 andfrontal attachment 304. Connector housing 302 further comprisesgenerally cylindrical barrel 306 and needle retraction cavity 310 thatare molded or otherwise fabricated as a unitary or unitized structuretogether with base 326 (FIG. 37). Base 326 desirably comprises forwardlyfacing, laterally spaced-apart openings into needle retraction cavity320 and into cylindrical bore 334 that communicates with fluid chamber352 (FIG. 39) disposed inside barrel 306. Opposed stop members 328, 330(FIG. 37) are provided to limit the range of travel of connector housing306 (FIGS. 34-36) relative to frontal attachment 304 during needleretraction, as discussed above in relation to medical device 200 ofFIGS. 24-33. As shown in FIGS. 34-42, plunger handle 308 with forwardlyfacing plunger seal 324 is desirably longitudinally slidable insidebarrel 306 and can be inserted or withdrawn relative to barrel 306 tovary the volume of fluid chamber 352 as needed for aspiration, injectionor extraction through fluid pathway 354 (FIG. 39) communicating with thefront end of fluid chamber 352.

Referring to FIGS. 34-37, 43 and 44, frontal attachment 304 desirablyfurther comprises body 312 having a rearwardly facing pair of opposedupper and lower laterally disposed clip members 315 having beveledsurfaces adapted to slip over and snap into lateral sliding engagementwith upper and lower rails disposed between opposed stop members 328,330 of base 326 of body 312. As seen in FIG. 44, the square shoulderdisposed on the back of each of upper and lower clip members 315desirably maintain frontal attachment 304 in sliding engagement withbody 312 along at least one laterally extending, sliding interface.Annular fluid seal 336 (FIGS. 37, 39 and 42) is desirably providedbetween connector housing 302 and frontal attachment 304 to limit fluidleakage between them when slidably engaged and when medical device 300is being used.

Referring more particularly to FIGS. 37, 39 and 42, frontal attachment304 also desirably comprises a needle retraction mechanism comprisingneedle holder 338 and attached retractable needle 340, and a biasingmember such as coil spring 342 exerting a rearwardly directed biasingforce against needle holder 338 to facilitate withdrawal of needle 340from a patient, vial or other fluid source or receptacle during needleretraction as discussed below. The front end of spring 342 is desirablyseated inside nose 344 and the elongate portion of needle holder 338 isdesirably inserted inside spring 342 and spring 342 is desirably held incompression until frontal attachment 304 is engaged with base 326 ofconnector housing 302 during assembly. Annular fluid seal 336 isdesirably seated inside cylindrical bore 334 (FIG. 37) prior to theattachment of frontal attachment 304 to connector housing 302 and therearwardly facing surface of needle holder 338 is desirably pressed intoabutting engagement with the facing portion of seal 336 by compressedspring 342.

Prior to use, removable needle cover 314 (FIGS. 34 and 37-39) isdesirably installed into frictional engagement with nose 344 (FIG. 37)of body 312 to protect needle 340 from being dulled or contaminated andto protect those handling medical device 300 from an inadvertent needlestick prior to use. As shown, needle cover 314 desirably comprisesforwardly projecting locking arm 318 that is received into the frontopening of needle retraction cavity 320 and prevents premature relativesliding movement between connector housing 302 and frontal attachment304 prior to use. It will be appreciated, however, upon reading thisdisclosure that other similarly effective locking devices can also beprovided and used to prevent premature lateral shifting or repositioningof connector housing 302 relative to frontal attachment 304 of medicaldevice 300 prior to use.

Frontal attachment 304 desirably further comprises laterally facingtextured surface 322 configured for use in applying pressure orresistance force in a direction transverse to the direction of fluidflow through needle 340 and fluid pathway 354 to initiate needleretraction following use. Such pressure or resistance, when combinedwith oppositely directed pressure applied to some portion of connectorhousing 302, facilitates lateral repositioning of connector housing 302relative to frontal attachment 304 to interrupt fluid flow through fluidpathway 354 and initiate needle retraction following use. Lateralmovement of connector housing 302 relative to frontal attachment 304disengages the forwardly facing surface of annular seal 336 from therearwardly facing surface of needle holder 338 and causes annular seal336 to slide laterally into engagement with the rearwardly facingsurface of body 312, thereby blocking off any fluid flow forwardly fromsyringe barrel 306 or cylindrical bore 334 subsequent to suchrepositioning.

Relative lateral movement between connector housing 302 and frontalattachment 304 is limited to travel between a first position (FIG. 35)where needle 340 is forwardly extending from frontal attachment 304 insubstantially coaxial alignment with syringe barrel 306 and a secondposition (FIG. 36) where the needle is retracted to a safe positionfollowing use and no longer projects forwardly from nose 344 (FIG. 37)and body 312. As the rearwardly facing head of needle holder 338 movesinto substantial coaxial alignment with the front facing opening intoneedle retraction cavity 320 of needle retraction chamber 310, therearwardly directed biasing force of spring 342 forces needle holder 338rearwardly into the closed rear end of needle retraction chamber 310.The rear end of needle retraction chamber 310 can be vented if desiredso long as needle holder 338 remains captured inside needle retractioncavity 310. Because spring 342 and needle 340 typically bridge the gapbetween needle retraction chamber 310 and body 312 of frontal attachment304, frontal attachment 304 is thereafter held in the second positionand cannot be returned to the first position without impermissiblydisassembling the used medical device 300.

Referring generally to FIGS. 45-59, medical device 400 of the inventioncan also comprise a filter plug 420 disposed in liquid-tight engagementinside opening 422 in frontal attachment 402 to facilitate use ofmedical device 400 for collecting and transferring blood gas samples forfurther processing by known methods. Filter plug 420 is desirably madeof any known material that will allow pressurized air to be expelledthrough filter plug 420 without permitting leakage of blood throughfilter plug 420. Following collection of a blood sample also containingarterial blood gas, needle 410 can be retracted by shifting frontalattachment 402 laterally relative to connector housing 404 attached tosyringe 450, and into alignment with needle retraction cavity 444 insideneedle retraction chamber 432, which also shifts filter plug 420 intoalignment with seal 428 and with fluid flow path 427 into the syringe toprevent collected blood from leaking out pending further processing.After needle retraction, syringe 450 can be rotated, most preferably toa vertical position, thereby allowing any excess air to flow upwardlytoward filter plug 420 as plunger handle 456 is advanced inside syringebarrel 452 until blood touches filter plug 420, at which time medicaldevice 400 and associated syringe 450 is ready for further processing.

More particularly, FIGS. 45-53 depict an embodiment of medical device400 of the invention comprising frontal attachment 402, connectorhousing 404, and retractable needle assembly 406 further comprisingneedle 410, needle retraction spring 408, and needle holder 412. Priorto needle retraction, spring 408 is desirably compressed and needleholder 412 is seated inside forwardly extending nose 414 of frontalattachment 402. Connector housing 404 desirably further comprises body424 having a first opening 430 that is part of fluid flow path 427extending into and through connector body 434. Diametrically opposed,radially projecting tabs 436 are provided for use in releasablyconnecting an associated medical device such as syringe 450 that isdepicted in FIGS. 54-59. Opening 444 in body 424 desirably providesentry into a needle retraction cavity disposed inside substantiallycylindrical needle retraction chamber 432 disposed in laterallyspaced-apart and substantially parallel relation to connector body 434that is initially coaxially aligned with needle 410 when frontalattachment 402 is assembled with connector housing 404 by attachmentmeans such as opposed clips 426 as previously described in relation toother embodiments of the invention. A needle cover 438 is desirablyprovided to protect needle 410 and locking arm 440, which engagesopening 444, is desirably provided to prevent premature needleretraction while cover 438 is in place. Frontal attachment 402preferably further comprises a contact surface 418 against whichpressure can be exerted by the user to initiate needle retractionfollowing removal of needle cover 438 and use of medical device 400 todraw a fluid sample from which the blood gas can be analyzedsubsequently by known procedures.

Referring more particularly to FIGS. 54-59, medical device 400 of theinvention can be satisfactorily used with a conventional luer locksyringe 450 attached to connector housing 404 and further comprisingbarrel 452, plunger handle 456, plunger cap 460, plunger seal 462, andvariable volume fluid chamber 464 communicating with fluid flow path 427(seen better in FIG. 51). After a blood sample is drawn, frontalattachment 402 medical device 400 is repositioned laterally by the userso that needle 410 moves out of alignment with syringe 450 and intoalignment with needle retraction chamber 432, thereby permittingretraction. At the same time, filter plug 420 is moved into alignmentwith syringe 450 so that any excess air captured between filter plug 420and plunger seal 462 can be expelled by advancing syringe handle 456 byapplying pressure to plunger cap 460 prior to further processing of theblood sample and analysis of the blood gas contained in variable volumefluid chamber 464.

Importantly, the medical devices disclosed here can be manufactured andassembled with broader tolerances than are otherwise required forconventional medical devices having plunger-activated retractableneedles, with an associated reduction in manufacturing cost that canprovide a basis for pricing at lower costs for medical providers andconsumers. Other benefits are also associated with having a laterallyspaced-apart needle retraction cavity and a sequence of operation thatdoes not require cutting, breaking or the use of conventional retaineror holding members disposed between the needle retraction mechanism anda wall of a syringe barrel.

Although luer connectors and compression springs are satisfactory foruse in the present invention, it should be understood that otherconnectors and biasing members can also be used provided that theyotherwise meet the general parameters of the invention as disclosed andclaimed here. Other alterations and modifications of the invention willlikewise become apparent to those of ordinary skill in the art uponreading this specification in view of the accompanying drawings, and itis intended that the scope of the invention disclosed herein be limitedonly by the broadest interpretation of the appended claims to which theinventors are legally entitled.

We claim:
 1. A medical device useful for blood and blood gas samplingthat is selectively attachable to and detachable from a conventionalneedleless syringe having a plunger, the medical device comprising: afrontal attachment further comprising a forwardly projecting retractableneedle, a needle retraction assembly, and a filter plug laterally spacedapart from the needle retraction assembly; and a connector housingfurther comprising a connector body attachable to the needlelesssyringe, and a needle retraction chamber laterally spaced apart from theconnector body; wherein the frontal attachment and the connector housingare disposed in adjacent and laterally slidable relation to each otherwith the retractable needle and the connector body aligned during bloodand blood gas sampling with a sealing element disposed between them torestrict fluid leakage during any relative movement between them; andwherein, following blood and blood gas sampling when attached to aneedless syringe, the retractable needle is retracted by shifting thefrontal attachment laterally relative to the connector housing until theretractable needle is aligned with a needle retraction cavity inside theneedle retraction chamber, which also shifts the filter plug intoalignment with the connector body to prevent leakage of blood out of themedical device while permitting excess air to be expelled through thefilter plug by advancing the plunger of the needleless syringe relativeto the filter plug following needle retraction.
 2. The medical device ofclaim 1 in combination with a needless syringe.
 3. The medical device ofclaim 1 wherein the filter plug is disposed in liquid-tight engagementinside an opening in the frontal attachment.
 4. The medical device ofclaim 1 wherein the filter plug is made of material that allowspressurized air to be expelled through the filter plug withoutpermitting leakage of blood through the filter plug.
 5. The medicaldevice of claim 1 wherein the connector body comprises a luer connector.